The subpoena deadline was Monday and Trump Jr. intended to let the committee know he would not show up, according to the source. His lawyers had drafted a letter, reviewed by USA TODAY, saying they would not allow Trump Jr. to testify before the committee.

They had not yet sent the letter when a staff member of the Senate Intelligence Committee called Trump Jr.’s legal team Monday afternoon and said they were willing to negotiate, and extended the deadline until 5 p.m. on Tuesday. The deal was announced Tuesday afternoon.

Sen. Lindsey Graham, chairman of the Senate Judiciary Committee and close ally to President Donald Trump, on Sunday said if he was Trump Jr.'s lawyer, he would advise him not to testify. On Monday, Graham clarified his earlier remarks and said that the president's son should "show up and plead the Fifth."

The subpoena threatened to rip open a rift within the Republican Party if Trump Jr. did not show up, and the committee would have had to decide how to proceed.

The president last week said he was surprised by the move from lawmakers.

"My son’s a very good person. My son was totally exonerated," Trump told reporters last week, referring to special counsel Robert Mueller's probe into Russian interference in the 2016 presidential election.